QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Data Supplement Erratum All Versions of this Article: jpet.108.146225v1 jpet.108.146225v2 329/1/252    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Minuesa, G. Articles by Martinez-Picado, J. Search for Related Content PubMed PubMed Citation Articles by Minuesa, G. Articles by Martinez-Picado, J.

METABOLISM, TRANSPORT, AND PHARMACOGENOMICS

Transport of Lamivudine [(-)-β-L-2',3'-Dideoxy-3'-thiacytidine] and High-Affinity Interaction of Nucleoside Reverse Transcriptase Inhibitors with Human Organic Cation Transporters 1, 2, and 3

IrsiCaixa Foundation, Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain (G.M., I.E., B.C., J.M.-P.); Institüt für Anatomie und Zellbiologie, Universität Würzburg, Würzburg, Germany (C.V., V.G., P.A., H.K.); Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Institut de Biomedicina, Universitat de Barcelona and Centro de Investigación Biomédica en Red-Enfermedades Hepáticas y Digestivas, Barcelona, Spain (M.M.-A., M.P.-A.); and Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain (J.M.-P.)

Nucleoside reverse transcriptase inhibitors (NRTIs) need to enter cells to act against the HIV-1. Human organic cation transporters (hOCT1–3) are expressed and active in CD4+ T cells, the main target of HIV-1, and have been associated with antiviral uptake in different tissues. In this study, we examined whether NRTIs interact and are substrates of hOCT in cells stably expressing these transporters. Using [³H]N-methyl-4-phenylpyridinium, we found a high-affinity interaction among abacavir [[(1S,4R)-4-[2-amino-6-(cyclopropylamino)purin-9-yl]-cyclopent-2-enyl]methanol sulfate] (ABC); <0.08 nM], azidothymidine [3'-azido-3'-deoxythymidine (AZT); <0.4 nM], tenofovir disoproxil fumarate (<1.0 nM), and emtricitabine (<2.5 nM) and hOCTs. Using a wide range of concentrations of lamivudine [(-)-β-L-2',3'-dideoxy-3'-thiacyitidine (3TC)], we determined two different binding sites for hOCTs: a high-affinity site (K_d1 = 12.3–15.4 pM) and a low-affinity site (K_d2 = 1.9–3.4 mM). Measuring direct uptake of [³H]3TC and inhibition with hOCT substrates, we identified 3TC as a novel substrate for hOCT1, 2, and 3, with hOCT1 as the most efficient transporter (K_m = 1.25 ± 0.1 mM; V_max = 10.40 ± 0.32 nmol/mg protein/min; V_max/K_m = 8.32 ± 0.40 µl/mg protein/min). In drug-drug interaction experiments, we analyzed cis-inhibition of [³H]3TC uptake by ABC and AZT and found that 40 to 50% was inhibited at low concentrations of the drugs (K_i = 22–500 pM). These data reveal that NRTIs experience a high-affinity interaction with hOCTs, suggesting a putative role for these drugs as modulators of hOCT activity. Finally, 3TC is a novel substrate for hOCTs and the inhibition of its uptake at low concentrations of ABC and AZT could have implications for the pharmacokinetics of 3TC.

Address correspondence to: Javier Martinez-Picado, IrsiCaixa Foundation, Hospital Germans Trias i Pujol, E-08916, Badalona, Barcelona, Spain. E-mail: jmpicado{at}irsicaixa.es

This article has been cited by other articles:

				C. Volk, V. Gorboulev, A. Kotzsch, T. D. Muller, and H. Koepsell Five Amino Acids in the Innermost Cavity of the Substrate Binding Cleft of Organic Cation Transporter 1 Interact with Extracellular and Intracellular Corticosterone Mol. Pharmacol., August 1, 2009; 76(2): 275 - 289. [Abstract] [Full Text] [PDF]

				W.-K. Lee, M. Reichold, B. Edemir, G. Ciarimboli, R. Warth, H. Koepsell, and F. Thevenod Organic cation transporters OCT1, 2, and 3 mediate high-affinity transport of the mutagenic vital dye ethidium in the kidney proximal tubule Am J Physiol Renal Physiol, June 1, 2009; 296(6): F1504 - F1513. [Abstract] [Full Text] [PDF]